Anti-drill and pick-proof guts make this a super-secure package. Ballistic plastic holds up to the most aggressive trashing and thrashing. Dual Steel Bar locking mechanism delivers up to 10 tons of pull strength. Features a massive 13mm (1/2 inch) hardened-steel shackle for strength. Lock is tough but gentle on your bike's finish; plastic, rubber or vinyl is used where lock might contact bike. Lock uses the legendary M-Cylinder mechanism for theft deterrence. The mini Bulldog is tough yet weighs under two pounds.